A United Nations report has found that Earth's protective ozone layer is slowly healing itself.联合国的一份报告发现，保护地球的臭氧层正在缓慢自我修复。 Ozone is a form of oxygen.臭氧是氧的一种形式。 In Earth's upper atmosphere, it acts as a barrier to block harmful radiation from the sun.在地球上层大气中，它是阻挡太阳有害辐射的屏障。 But closer to Earth's surface, ozone is a common pollutant.但在更靠近地球表面的地方，臭氧是一种常见的污染物。 At ground level, high levels of ozone can harm people's lungs and damage plants.在地面，高浓度的臭氧会伤害人的肺部和植物。 Research has shown that chemical pollutants released into the atmosphere shrink the ozone layer over time.研究表明，释放到大气中的化学污染物会随着时间的推移缩小臭氧层。 The layer exists in a part of Earth's atmosphere known as the stratosphere.这一层存在于地球大气中被称为平流层的部分。 The layer sits between 15 to 30 kilometers above Earth's surface.这一层位于地球表面上方15至30公里处。 Each year, a large hole develops in the layer over Antarctica.每年，南极洲上空都会出现一个大洞。 In their new report, U.N. scientists say at the current rate, the ozone hole over Antarctica would be fully healed by 2066.联合国科学家在他们的新报告中说，按照目前的速度，南极洲上空的臭氧空洞将在2066年完全愈合。 Paul Newman is the co-chair of the U.N. report.保罗·纽曼(Paul Newman)是这份联合国报告的联合主席。 It was recently presented at a meeting of the American Meteorological Society.该研究最近在美国气象学会的一次会议上发表。 He told The Associated Press, "In the upper stratosphere and in the ozone hole we see things getting better."他对美联社表示，“在平流层上层和臭氧空洞中，我们看到情况正在好转。” However, the researchers reported the healing is happening very slowly.然而，研究人员报告说，修复的过程非常缓慢。 The worldwide average amount of ozone is estimated to return to pre-thinning levels around 2040, the report said.报告称，据估计，全球臭氧的平均量将在2040年左右恢复到变薄前的水平。 A 1987 agreement called the Montreal Protocol banned a series of chemicals – mainly used in refrigerants and aerosols – believed to have reduced the thickness of the ozone layer.1987年签署的《蒙特利尔议定书》禁止使用一系列被认为会降低臭氧层厚度的化学物质，这些化学物质主要用于制冷剂和气溶胶。 The Secretary-General of the World Meteorological Organization, Petteri Taalas, commented about the report in a statement.世界气象组织秘书长佩特里·塔拉斯在一份声明中对这份报告发表了评论。 He said past actions taken to reduce ozone damage had demonstrated the importance of limiting climate-harming substances.他说，过去为减少臭氧破坏所采取的行动已经证明了限制对气候有害物质的重要性。 Newman added that while signs of healing were reported four years ago, researchers were looking for more lasting change.纽曼补充说，虽然四年前就有修复迹象的报道，但研究人员正在寻找更持久的改变。 The earlier recovery numbers had "solidified a lot," he said.他说，早些时候的修复数据已经“稳固了很多”。 The two main chemicals that eat away at ozone are in lower levels in the atmosphere, said Newman, who is also the chief Earth scientist at NASA's Goddard Space Flight Center.纽曼也是美国宇航局戈达德太空飞行中心的首席地球科学家，他说，侵蚀臭氧的两种主要化学物质在大气中含量较低。 The report said chlorine levels were down 11.5 percent since they reached a high in 1993.报告称，氯含量自1993年达到峰值以来下降了11.5%。 Bromine – which does a better job of eating ozone but exists at lower levels in the air – dropped 14.5 percent since reaching a high point in 1999.溴能更好地吞噬臭氧，但在空气中的含量较低，自1999年达到最高点以来下降了14.5%。 Newman said the reductions in chlorine and bromine levels came largely because of the limits set in the Montreal Protocol.纽曼说，氯和溴含量的降低主要是因为《蒙特利尔议定书》规定的限制。 Another member of the research team was David W.Fahey, director of the U.S. National Oceanic and Atmospheric Administration's chemical sciences lab.研究小组的另一名成员是美国国家海洋和大气管理局化学科学实验室主任大卫·W·费伊。 He said the latest results show there has been a "sea change" in the way the world deals with its ozone-thinning substances.他说，最新的结果表明，世界处理导致臭氧稀薄的物质的方式发生了“翻天覆地的变化”。 Natural weather cycles in the Antarctic also affect ozone hole levels, which are highest in the autumn.南极的自然天气周期也会影响臭氧空洞水平，臭氧空洞水平在秋季最高。 The past few years, Newman said, the ozone hole grew a bit bigger because of that.纽曼说，在过去的几年里，臭氧空洞因此而变得更大。 But overall, the results demonstrate clear healing, the report said.但报告称，总体而言，结果显示出明显的修复迹象。 I'm Bryan Lynn.布莱恩·林恩报道。